You can find a variety of resources in Animal Crossing: New Horizons that you can use to build up your island, crafting brand new items and furniture pieces you can show off in your home or place them in the environment. When a meteor shower occurs in the game, you have a chance to make a wish to have star fragments fall from the sky. However, you can also have Aries fragments fall.
Aries fragments are rare pieces of star fragments you can have fall in New Horizons, and they only show up during April. There are two different star fragments you can receive when you wish upon the meteor shower: Star fragments and large star fragments, which are named after the monthly zodiac sign. From March 21 to April 19, you will receive Aries fragments.
To have them fall with the traditional star fragments, you need to keep wishing on the stars during a meteor shower. Consistently wishing while the stars fall is the best way to have them show up. The next day, roam around your beach and try to find any of them that are washing up on your shore. You want to walk your entire island several times because they can continue washing up while you run around.
Aries fragments and star fragments are rare, much like the meteor showers themselves. Try to optimize on their presence as much as you can, and you should be able to make the most of it. You want to save any Aries fragments you find to see if you can make anything special with them later in New Horizons.